Port plug for a respiratory mask



FIG. 1 is a perspective view of a port plug for a respiratory mask according to an embodiment of my design;

FIG. 2 is a rear view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof; and,

FIG. 5 is a bottom view thereof.

Where included, broken lines showing environment or structure are for illustrative purposes only and form no part of the claimed design. Where included, dotted lines represent the border between claimed and unclaimed subject matter and form no part of the claimed design. 

The ornamental design for a port plug for a respiratory mask, as shown and described. 